Thermodynamic Modeling of Chemical Equilibria in Metal Extraction

Abstract

Models of equilibrium extraction data are being developed for use in computer simulations of metal extraction processes. The correlations are based on chemical mass action principles in which the effects of metal complexation and aqueous phase activity coefficients are considered. Activity coefficients in mixed electrolyte solutions at high ionic strengths are calculated using methods available in the literature. This modeling approach is demonstrated for HNO₃ extraction with both the PUREX and TRUEX solvents and for Am³⁺ extraction by octylphenyl-N, N-diisobutylcarbamoylmethylphosphine oxide, which is the primary extractant in the TRUEX solvent.